Drug Testing and Analysis最新文献

The effective implementation of drug precursor legislation has driven the innovation and design of new alternative substances. The application of 1,3-dicarbonyl precursors as alternative precursors for the synthesis of 1-phenyl-2-propanone (P2P) and 3,4-methylenedioxyphenyl-2-propanone (MDP2P) has created new challenges to legal control. Their 1,3-dicarbonyl structure allows the precursors to exist as an equilibrium mixture of the tautomeric diketo and keto-enolic forms during the nuclear magnetic resonance (NMR) analysis. In this study, the keto-enol tautomerism of four 1,3-dicarbonyl drug pre-precursors, α-phenylacetoacetamide (APAA), methyl α-phenylacetoacetate (MAPA), ethyl α-phenylacetoacetate (EAPA), and methyl 2-(benzo[d][1,3]dioxol-5-yl)-3-oxobutanoate (MAMDPA) were investigated through NMR. One-dimensional (1D) and 2D NMR were combined to assign signals for the diketo and keto-enolic tautomers. Results showed that the keto-enol tautomerism was solvent-dependent but was also influenced by the substituent present in the molecule. Further, the analysis results indicated that majority of substances existed mainly in the diketo form. The enol-keto equilibrium constant (K_eq) was stable in dimethyl sulfoxide-d₆ and chloroform-d, while unstable for some compounds in acetone-d₆ and deuterated methanol. The presence of impurities in the seized sample may disrupt the equilibrium between keto-enol tautomers in 1,3-dicarbonyl precursors. After the optimization of several key quantitative parameters, a quantitative NMR method for the quantification of 1,3-dicarbonyl drug precursors were also developed to facilitate their quantitative analysis. This is the first study to investigate the keto-enol tautomerism and quantification of 1,3-dicarbonyl drug precursors by NMR, providing a new approach for structure analysis and quantification of new precursor analogues.

Salbutamol is a common short-acting beta₂-adrenergic agonist used in treatment of asthma and exercise-induced bronchoconstriction but also possesses anabolic and metabolic actions in skeletal muscle. As a chiral compound, salbutamol is a racemic 1:1 mixture of two enantiomers, (R)-salbutamol and (S)-salbutamol, which exhibit divergent pharmacokinetic and pharmacodynamic actions. Despite salbutamol being available for decades, information on the enantioselective disposition of salbutamol enantiomers in human skeletal muscle is absent. In this study, we determined concentrations of (R)-salbutamol and (S)-salbutamol by UHPLC-MS/MS in arterial plasma and vastus lateralis muscle samples from 12 lean young men 2½ and 7 h following ingestion of 24 mg oral salbutamol. Mean (range) arterial plasma concentrations were 10-fold higher (p < 0.001) for (S)-salbutamol than (R)-salbutamol, being 33(9-62) and 49(30-84) ng·mL^-1 for (S)-salbutamol and 4 (1-6) and 4 (2-5) ng·mL^-1 for (R)-salbutamol 2½ and 7 h following administration, respectively, reflecting faster elimination of the (R)-enantiomer. Mean (range) muscle concentrations were higher (p < 0.001) for (S)-salbutamol than (R)-salbutamol 2½ h (0.17 [0.1-0.26] vs. 0.04 [0.02-0.06]) and 7 h (0.31 [0.21-0.46] vs. 0.06 [0.04-0.12] ng·mg_d.w. ^-1) after administration. However, muscle:plasma partition coefficient was two-fold higher (p < 0.001) for (R)-salbutamol than (S)-salbutamol 7 h following administration. These observations demonstrate that oral salbutamol exhibits enantioselective disposition in systemic circulation and muscle favoring the (S)-enantiomer but with higher relative partitioning of the (R)-enantiomer in skeletal muscle. Furthermore, the concentration-time profiles of salbutamol enantiomers are different in skeletal muscle and systemic circulation following oral ingestion. These findings have implications for the application of chiral switch (R)-salbutamol in doping control.

Phosphatidylethanol (PEth) has become an important marker to assess drinking behaviour and monitor abstinence. Despite its increasing use, knowledge on robustness and standardization and comparability of methods and results are still limited. In 2022, the first international consensus for the use of PEth and its interpretation was published. To establish an experience-based foundation for further harmonization, three rounds of interlaboratory comparison using microsamples were conducted. Participating laboratories sent their sampling devices to the laboratory of Forensic Toxicology at the University of Bern, where for each round, four different authentic blood samples were applied to the devices and sent back. The PEth 16:0/18:1 target concentrations covered a range between 16 and 474 ng/mL (0.023 and 0.676 μmol/L, respectively) and included sample concentrations close to the decision limits of 20 and 200 ng/mL (0.025 and 0.28 μmol/L, respectively). Evaluation of the results based on guidelines by Horwitz and the Society of Toxicological and Forensic Chemistry (GTFCh) showed that 73% of all participating laboratories quantified and reported all samples (N = 4 for each round) within the acceptable limits. More than 90% quantified and reported at least one sample within the acceptable limits.

Monitoring of drug use in athletes is of interest both for health and competition-related issues. Considering the advantages of Dried Blood Sampling (low invasiveness, easy sampling, long term storage), we have validated a quantitative LC-MS/HRMS method for the screening of 16 nonsteroidal anti-inflammatory drugs. For all drugs, accuracy and imprecision were within 15% for the 3 levels of quality control and lower than 20% for the lower limit of quantification. Application was performed from samples obtained for Ultra-Trail du Mont-Blanc® 2021 and 2022. A focus on ibuprofen and its metabolites (hydroxyibuprofen, carboxyibuprofen, ibuprofen glucuronide and hydroxyibuprofen glucuronide) was made because the results showed that it was the most detected nonsteroidal anti-inflammatory drug. Further, an interpretation of the ibuprofen concentrations was proposed either from experimental data obtained after an intake of ibuprofen by 10 control subjects, or from a pharmacokinetic modelling and simulations. Depending on the analytical performances of the method, we proposed possible detection windows for ibuprofen in runners. The pharmacokinetic model made it possible to consider two scenarios with and without modification of the total clearance of ibuprofen linked to a modification of the pharmacokinetics of the drugs due to the practice of a long and intense physical activity.

The fast skeletal troponin activators (FSTAs) Reldesemtiv and Tirasemtiv were developed for patients suffering from neuro-degenerative diseases of the motor nervous system, e.g. amyotrophic lateral sclerosis (ALS). The drug candidates can increase the sensitivity of troponin C to calcium by selectively activating the troponin complex resulting in increased skeletal muscle contraction. Although the development of the drug candidates is currently discontinued because of missed end points in phase III clinical studies with patients with ALS, phase I clinical trials showed an increase in muscle contraction force in healthy humans. This effect could be abused by athletes to enhance performance in sports. As the substances are listed on the 2024 edition of the World Anti-Doping Agency's Prohibited List, the aim of this study was to identify and characterize metabolites of Reldesemtiv and Tirasemtiv to ensure their reliable identification in doping control analyses. The biotransformation of the drug candidates was studied in vitro using pooled human liver microsomes and 3D cultivated human hepatic cells of the cell line HepaRG, yielding a total of 11 metabolites of Reldesemtiv and eight of Tirasemtiv. In addition, a human elimination study was conducted to investigate the metabolism and elimination profile of Tirasemtiv and Reldesemtiv in vivo, suggesting the N-glucuronide of Tirasemtiv and hydroxylated 3-fluoro-2-(3-fluoro-1-methylcyclobutyl)pyridine as well as its glucuronide as suitable target analytes for routine doping controls. Applying a validating HPLC-MS/MS method, optimized to detect Reldesemtiv and Tirasemtiv in human urine, microdosing (50 μg) of each substance was traceable for 24-72 h.

The non-psychoactive cannabinoids cannabidiol (CBD) and cannabidiolic acid (CBDA) are available on the market in different forms, mostly for their anti-inflammatory and potential analgesic properties. These substances are prohibited during equine competitions. CBD and CBDA are naturally present in hemp straw, commonly used as a bedding substitute for wheat straw. Unfortunately, horses can eat it, which therefore could lead to a possible risk of positive findings for CBD/CBDA in biological samples after doping control tests. The goals of this study were, first, to provide recommendations on the use of hemp straw before competition and, second, to assess if discrimination between hemp bedding exposure and CBD oil administration is possible. Several CBD equine in vivo studies have been conducted, including one on hemp straw used as bedding and one after administration of CBD oil by topical and sublingual routes. In hemp straw, CBDA was detected in higher quantities than CBD, and other cannabinoids have been observed. After hemp straw exposure, CBDA was also detected in higher quantities than CBD in all urine samples. It appeared that hemp straw should not be used as bedding for equine competition except if a delay of at least 48 h is respected. Regarding the CBD oil product analysis, CBD was the main compound detected. After administration, 7-hydroxy CBD was identified in the urine. In conclusion, based on these data, we highlighted that it could be possible to discriminate the exposure of a horse to hemp straw from an administration of a CBD oil product thanks to the main presence of CBDA.

Despite the fact that drugs of abuse are illegal, a drug-free festival still remains an utopia in most settings. For law enforcement purposes, it is necessary to rapidly determine whether controlled substances are involved. On-site testing is a challenging task because drugs appear in different physical forms and concentrations. The aim of this study was to compare the performance of two spectroscopic techniques, Raman and Fourier transform-infrared (FT-IR), for the testing of drug seizures at a dance festival. First, samples were measured through packaging with Raman. Subsequently, homogenized samples were analysed with FT-IR. For MDMA tablets, a chemometric model was applied on the FT-IR spectra for the dose estimation. After the festival, results were confirmed in the forensic laboratory with gas chromatography coupled with mass spectrometry (GC-MS) and gas chromatography with flame ionization detection (GC-FID). In total, 166 samples of which 90 tablets, 53 powders, 16 crystals and 7 liquids were analysed. MDMA, cocaine and ketamine were the top three drugs seized. The Raman technique was suitable for powders and crystals (sensitivity of 100% and 81%, respectively). However, in comparison with FT-IR, Raman performance was lower for the analysis of liquids (sensitivity of 67%) and 'ecstasy'-like tablets (sensitivity of 41%). Overall, sensitivities above 95% were obtained with FT-IR. The MDMA doses of the tablets, determined on-site, ranged between 52 mg and 336 mg MDMA hydrochloride. For a quick identification of a variety of drugs on-site, the combination of Raman and FT-IR is recommended. It should be emphasized that optimized settings, in-house libraries and analysis by trained operators are essential to obtain correct results.

An improved screening workflow and a robust capillary flow LC-MS confirmatory method for the detection of recombinant human erythropoietin (rHuEPO) has been implemented to increase the sensitivity of rHuEPO detection and to reduce the number of suspect samples committed to confirmatory testing. The influence of repeated dosing of epoetin-β on the detection window of rHuEPO in equine plasma was assessed using the optimised method. Samples were initially assessed using an economical R&D Human EPO Duo-Set ELISA Development System. Samples indicating a result greater than the batch baseline were analysed using the complementary R&D Human EPO Quantikine IVD ELISA kit. All samples recording an abnormal screening result were subjected to confirmatory analysis. Confirmation of rHuEPO in plasma (≥2.5 ml) in the range of 4-13 mIU/ml (n = 6) was achieved using immunoaffinity enrichment, tryptic digestion, and capillary flow LC-MS/MS. Four horses were administered a single dose of epoetin-β (10,000 IU) via the subcutaneous and intravenous routes, on two occasions, seven days apart. The excretion profile was rapid with epoetin-β detection times of 48 to 72 h following each administration, with no appreciable difference observed between the two routes of administration. This workflow has been shown as an effective anti-doping strategy related to rHuEPO misuse and supports the use of out-of-competition testing of horses in the 2 to 3-day period prior to race-day.

The identification of trimetazidine, a medicine used for treating stable angina pectoris and for preventing angina attacks, has been recently observed in doping cases involving high profile athletes from various countries over the world. In all the files where the authors have been involved, the urine concentration of trimetazidine was low (<2 ng/mL), and the athletes argued that contamination was the source of their adverse analytical finding. It is possible to challenge imposed sanctions in relation to an adverse analytical finding, but it is the responsibility of the athlete to demonstrate he/she is innocent and can qualify for no fault or negligence. When the delay between the urine collection and the notification of the violation was not too long (less than 6 months), these athletes requested a head hair test. Trimetazidine was analyzed by an original LC-MS/MS method involving pH 9.5 borate buffer overnight incubation of 20 mg and subsequent solvents extraction in presence of trimetazidine-D8 used as internal standard. Linearity was verified from 1 to 200 pg/mg (R² = 0.9987). Limit of detection of the method was 0.1 pg/mg. The hair specimen of a male subject, collected 4 weeks after single oral ingestion of 20 mg trimetazidine, tested positive at 146 pg/mg in the corresponding segment. Concentrations of trimetazidine measured in several hair specimens (n = 5) collected from athletes challenging their anti-doping rule violation were below 1 pg/mg, which is consistent with incidental exposure due to contamination. This is the first evidence that trimetazidine is incorporated in human hair after a single therapeutic dose administration.

Several protocols for the analysis of amphetamine-type stimulants (ATS) in hair have been developed over the years, with microextraction by packed sorbent (MEPS) being used for drugs like opiates, cocaine and ketamine. However, concerning ATS determination in hair samples, this approach has only been applied so far to amphetamine (AMP) and methamphetamine (MAMP). This study aimed at developing and validating a MEPS-based procedure for the determination in hair of not only AMP and MAMP but also of 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), 1-(1,3-benzodioxol-5-yl)propan-2-yl (ethyl)amine (MDE) and N-methyl-1-(1,3-benzodioxol-5-yl)-2-aminobutane (MBDB) as well. Hair, 50 mg, was incubated with 1 M sodium hydroxide (NaOH) at 45°C overnight, neutralization with 10 M hydrochloric acid (HCl) and centrifugation followed. The design of experiments approach was used for MEPS optimization, with the final optimized conditions including conditioning (250 μL methanol and deionized water), loading (18 × 100 μL) and elution (7 × 100 μL 2% NH₄OH in acetonitrile). The eluted extract was evaporated to dryness and underwent microwave-assisted derivatization with N-methyl-bis(trifluoroacetamide) (MBTFA), and it was afterwards injected onto the gas chromatography-mass spectrometer (GC-MS). The obtained recoveries ranged between 8% and 14% for AMP, 14% and 20% for MAMP, 10% and 15% for MDA, 18% and 28% for MDMA, 25% and 43% for MDE and 34% and 52% for MBDB, and the method was linear from 0.2 to 5.0 ng/mg. Precision and accuracy were in accordance with international method validation guidelines. This novel method involving MEPS coupled to GC-MS offers a swift, eco-friendly and cost-effective alternative to traditional procedures for detecting these AMPs in hair samples.